为什么这个 JavaFX 选项卡窗格示例不起作用

Question

My MainApp：

package multitabpane;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
public class MainApp extends Application 
{
  private Stage primaryStage;
  private AnchorPane rootLayout;  
 /** The horizontal offset for making the rootLayout movable */
  private double xOffset = 0;
 /** The vertical offset for making the rootLayout movable */  
  private double yOffset = 0;
  public MainApp() {}
  @Override
  public void start(Stage primaryStage){
    this.primaryStage = primaryStage;
    //Get rid of the windoze crap
    primaryStage.initStyle(StageStyle.UNDECORATED);
    initRootLayout();
    //Make the screen movable by a drag and drop 
    rootLayout.setOnMousePressed((MouseEvent event) -> {
      xOffset = event.getSceneX();
      yOffset = event.getSceneY();
    });
    rootLayout.setOnMouseDragged((MouseEvent event) -> {
      primaryStage.setX(event.getScreenX() - xOffset);
      primaryStage.setY(event.getScreenY() - yOffset);
    });
  }
 /**
  * Initializes the root layout.
  */
  public void initRootLayout() 
  {
    try 
    {
      // Load root layout from fxml file.
      FXMLLoader loader = new FXMLLoader();
     Loader.setLocation(MainApp.class.getResource("view/MainController.fxml"));
      rootLayout = (AnchorPane)loader.load();
      // Show the scene containing the root layout.
      Scene scene = new Scene(rootLayout);
      primaryStage.setScene(scene);
      primaryStage.show();
    } catch (IOException e) {}
  }
 /**
  * Returns the main stage.
  * @return
  */
  public Stage getPrimaryStage() {
    return primaryStage;
  }
  public static void main(String[] args){
    launch(args);
  }
    }

以下是 MainController

.java 和 MainController.xml

package multitabpane.view;
import javafx.fxml.FXML;
import javafx.scene.layout.AnchorPane;
public class MainController {
  // Inject tab content.
    @FXML private AnchorPane fooTabPage;
// Inject controller
    @FXML private FooTabController fooTabPageController;
// Inject tab content. Keep Commented out until the above is working
//    @FXML private BarTabPage barTabPage;
    // Inject controller 
//    @FXML private BarTabController barTabPageController;
}

和

<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1">
 <TabPane id="tabPane" prefHeight="400.0" prefWidth="600.0">
    <tabs>
        <Tab text="Tab 1">
            <content>
              <fx:include fx:id="fooTabPage" source="fooTabPage.fxml"/>
            </content>
        </Tab>
        <Tab text="Tab 2">
            <content>
              <!-- commented out until I can get the above to work -->
              <!-- fx:include fx:id="barTabPage" source="barTabPage.fxml"/ -->
            </content>
        </Tab>
    </tabs>
</TabPane>  
</AnchorPane>

这是FooTabController：

package multitabpane.view;
import javafx.fxml.FXML;
import javafx.scene.layout.AnchorPane;
class FooTabController {
  @FXML private AnchorPane fooTabPage;
}

最后这是FooTabPage.java和xml：

package multitabpane.view;
class FooTabPage {}

和

<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
    <AnchorPane fx:id="fooTabPage" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="multitabpane.view.FooTabController" />

最后是我尝试运行构建项目时的转储：

Executing D:J2EEMultiTabPanedistrun679227950MultiTabPane.jar using platform C:Program FilesJavajdk1.8.0_60jre/bin/java
Jun 21, 2017 9:14:22 AM multitabpane.MainApp initRootLayout
Error in MainApp:initRootLayout()
SEVERE: null
file:/D:/J2EE/MultiTabPane/dist/run679227950/MultiTabPane.jar!/multitabpane/view/fooTabPage.fxml:9
javafx.fxml.LoadException: 
file:/D:/J2EE/MultiTabPane/dist/run679227950/MultiTabPane.jar!/multitabpane/view/MainController.fxml:14

file：/

D：/J2EE/MultiTabPane/dist/run679227950/MultiTabPane.jar！/multitabpane/view/fooTabPage.fxml：9file：/D：/J2EE/MultiTabPane/dist/run679227950/MultiTabPane.jar！/multitabpane/view/MainController.fxml：14

at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.access$700(FXMLLoader.java:103)
at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:934)
at javafx.fxml.FXMLLoader$InstanceDeclarationElement.processAttribute(FXMLLoader.java:971)
at javafx.fxml.FXMLLoader$Element.processStartElement(FXMLLoader.java:220)
at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:744)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.access$2700(FXMLLoader.java:103)
at javafx.fxml.FXMLLoader$IncludeElement.constructValue(FXMLLoader.java:1143)
at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:746)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
at multitabpane.MainApp.initRootLayout(MainApp.java:58)
at multitabpane.MainApp.start(MainApp.java:35)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$163(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$176(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$174(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$175(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$149(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)

 Caused by: java.lang.IllegalAccessException: Class sun.reflect.misc.ReflectUtil can not access a member of class   multitabpane.view.FooTabController with modifiers ""
        at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:102)
        at java.lang.Class.newInstance(Class.java:436)
        at sun.reflect.misc.ReflectUtil.newInstance(ReflectUtil.java:51)
        at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:927)
        ... 24 more

Answer 1

我想这个问题可能是因为在类 MainController 中，您将 fooTabPage 声明为 FooTabPage 的实例，但在 MainController.fxml 中，您使用 <AnchorPane fx:id="fooTabPage"> ，简而言之，您在 fxml 和 java 类中声明了 fooTabPage 的不同类型。

只需更改代码

"@FXML private FooTabPage fooTabPage;" 

自

"@FXML private AnchorPane fooTabPage;" 

在主控制器中，问题将得到解决。因为在"fooTabPage.fxml"中，它的根元素是AnchorPane，所以你应该声明与fxml根窗格中使用的类型相同。

Answer 2

我已经通过将示例代码中的"foo"引用更改为基于"tab1"和"tab2"的更有意义的名称来解决这个问题。我现在运行构建项目时没有收到错误：

主控制器声明对选项卡的引用：

public class MainController {
   @FXML private AnchorPane tab1Page;   
   @FXML private AnchorPane tab2Page;
} 

在主控制器 fxml 中，将选项卡引用绑定到其文件源：

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="multitabpane.view.MainController">
  <TabPane id="tabPane" prefHeight="400.0" prefWidth="600.0">
    <tabs>
      <Tab text="Tab 1">
        <content>
          <fx:include fx:id="tab1Page" source="Tab1Controller.fxml"/>
        </content>
      </Tab>
      <Tab text="Tab 2">
        <content>
          <fx:include fx:id="tab2Page" source="Tab2Controller.fxml"/>
        </content>
      </Tab>
    </tabs>
  </TabPane>
</AnchorPane>

在选项卡中，控制器类为选项卡创建引用，并引用用户定义的选项卡工作区的任何其他控件。在我的解决方案中，每个选项卡控件层次结构中都有一个按钮和一个用于按钮"On Action"命令的侦听器：

public class Tab1Controller {
  @FXML Tab tab1; 
  @FXML Button exitButton;  
  @FXML
  public void exitApp()
  {
    System.exit(1);
  }
}

和

public class Tab2Controller 
{
  @FXML Tab tab2;
  @FXML Button resetButton;
  @FXML
  public void handleReset()
  {
    System.out.println("Does nothing");
  }
}

选项卡控制器必须相应地引用其控制器：

<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="multitabpane.view.Tab1Controller">
  <children>
    <Button fx:id="exitButton" layoutX="92.0" layoutY="136.0" mnemonicParsing="false" onAction="#exitApp" text="Button" />
  </children>
</AnchorPane>

和

 <AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/2.2" fx:controller="multitabpane.view.Tab2Controller">
  <children>
    <Button fx:id="resetButton" layoutX="78.0" layoutY="180.0" mnemonicParsing="false" onAction="#handleReset" text="Reset" />
  </children>
</AnchorPane>

总之，有一个主应用程序，三个控制器类和3个相应的FXML视图。